<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
       #box{
            width: 300px;
            height: 300px;
            margin: 0 auto;
        }
       #box span{
            display: block;
            width: 200px;
            height: 200px;
            margin: 0 auto;
       }
    </style>
</head>
<body>
<div id="box">
<span>您的验证码是:{{verification_code}}</span>
</div>
</body>
</html>